One: Preheat oven at 400°F. Transfer potatoes directly to oven rack and bake for 1 to 1 1/2 hour, until fork-tender. Remove from oven and set aside until just cool enough to handle. While still very warm, halve potatoes and scoop out flesh with a spoon; discard skins.

Two: With a potato ricer, squeeze warm potato flesh into a large, shallow bowl. Spread potato over bottom of bowl and set aside until cool, about 15 minutes.

Three: Drizzle egg over top of potato. Sprinkle with 1/4 cup flour and 1/2 teaspoon salt. With a fork, gently toss. With a rubber spatula, gently fold and press mixture until flour is incorporated and a dough forms. Lightly dust a flat work surface with remaining 1/4 cup flour. Turn dough out onto surface and knead until about half of dusting flour is incorporated and dough is no longer sticky but not overly stiff (TIP: Use as little flour as possible, just enough so dough no longer sticks to your hands or work surface). Form dough into a rectangle and use a dough scrapper or paring knife to divide into 4 equal pieces.

Four: Season a large pot of water with remaining pinch salt and bring to a simmer. Roll each piece of dough into a long rope about the thickness of your thumb. beginning in the center and working outward. Cut each rope into 1/2 to 1 inch pieces to form gnocchi. Working 10 to 15 pieces at a time, add gnocchi to pot and cook until each floats to the surface. Cook for 15 more seconds, then use a slotted spoon to transfer to a plate. repeat with remaining gnocchi.

Five: Meanwhile, in a large nonstick skillet, heat oil on medium-high. Add onion, celery and garlic and sauté, stirring often, until tender, about 5 minutes. Transfer to a medium bowl and set aside.

Six: Add mushrooms to skillet and sauté on medium-high until tender and beginning to release juices, about 5 minutes. Add 1/4 cup broth and deglaze pan by stirring up browned bits from bottom. Return onion mixture to skillet and stir in remaining 1/4 cup broth. Bring to a simmer.

Seven: Meanwhile, in a small bow, whisk arrowroot and 2 tablespoons cold water into a smooth paste. Slowly whisk paste into broth mixture. Return to a simmer, whisking until thickened. Add gnocchi, stirring to coat. Season with sage, pepper and salt to taste. To serve, top with cheese and pecans.